Regenerative heat exchanger



July 13, 1965 File d Sept. 10, 1962 SVEN-OLOF KRONOGARD REGENERATIVE HEAT EXCHANGER 2 Sheets-Sheet 1 July 13, 1965 SVEN-OLOF KRONOGARD REGENERATIVE HEAT EXCHANGER 'z Sheets-Sheet 2 Filed Sept. 10, 1962 United States Patent 3,194,302 REGENERATIVE HEAT EXQHANGER Sven-Olaf Kronogfird, Goteborg, Sweden, assignor to Aktiebolaget Volvo, Goteborg, Sweden, a corporation of Sweden Filed Sept. 10, 1962, Ser. No. 222,265 Claims priority, application Sweden, Sept. 11, 1961,

3 Claims. (or. res-e This invention relates to a rotary regenerative heat exchanger, particularly for gas turbine power plants, comprising a housing having an inlet and an outlet for a heating and a .heated elastic fluid, and a heat exchange member mounted for rotation in said housing and divided into a plurality of sections.

In gas turbine power plants for automotive purposes it is highly important to minimize the dimensions of the components of the plant. The heat exchanger is usually the largest one of these components.

In order to keep the dimensions of a heat exchanger as small as possible it is obviously desirable to utilize a heat exchange medium having a high heat capacity per unit volume. However, in addition to this, it as also necessary to utilize this medium to its maximum capa bilities.

In accordance with this invention, the sections of the heat exchange member are in the form of substantially wedge-shaped chambers having apertures for the supply and discharge of the fluids, said chambers being filled with a heat-absorbing material and arranged circularly around the axis of rotation with the apertures orientated in the direction of said axis, the annular zone of the part of the heat exchange member confronting the apertures extending radially over 50 to 90% of the radial extent of said sections. Due to the comparatively great radial extent of the part of the heat exchange member confronting the apertures there is obtained a very uniform distribution of the fluid over the end surface of the heat absorbing material even if this end surface be located at a relatively short distance within the plane of the apertures.

The invention is described herei'nbelow with reference to an embodiment illustrated in the annexed drawing. FIG. 1 is an axial sectional view of a regenerative heat exchangeraccording to the invention and FIG. 2 1s a partial sectional end view of this heat exchanger.

The heat exchanger illustrated in the drawing is intended for a gas turbine power plant in which the residual heat of the exhaust gases from the turbine is to be recovered and used for preheating the combustion air. The heat exchanger comprises a housing 1 and a cover la having a distributor chamber 2 for the air and a collecting chamber 3 for the exhaust gas, said chambers being separated from each other by means of a partition 4.

The cover In carries a central inlet duct 5 on which the heat exchange member is mounted for rotation by means of ball bearings 6.

The heat exchange member comprises an annular case having an outer wall 7 and an inner wall 8. The case also has end walls 9 and it which are flat at their outsides and have two sets of circular apertures 11 and t2, the apertures 11 being of larger diameter and located radially outwards of the apertures 12.

Inserted between the end walls 9 and iii are sheet metal receptacles defining chambers 13 for a heat absorbing material 14. As will be seen from FIG. 2, the chambers are substanially wedge-shaped and provided with openings corresponding to the apertures 11 and 12. The end walls of the chambers 13 are conically pressed outwards around the openings and carry cylindrical collars 15 which "ice are guided in the openings in the end walls of the case 7 and provided with sealing piston rings 16. Due to this arrangement the chambers 13 have a certain freedom of motion relative to the case 7, whereby to avoid detrimental thermal stresses.

The air arriving from the compressor of the turbine power plant passes via a space 17 in the housing 1 of the heat exchanger and through the inlet duct 5 to the distributor chamber 2 and hence passes through the heat exchange member from the left to the right, as viewed in FIG. 1. The exhaust gas from the turbine enters a distributor chamber 18 in the housing 1 of the heat exchanger and passes through the heat exchange member from the right to the left in FIG. 1. The gas leaves the collecting chamber 3 through a diagrammatically indicated outlet 19.

In order to prevent air from flowing over to the gas section of the heat exchanger, sealing members 20 and 21 are provided on either side of the heat exchange member. The seal-ing members have arc-shaped openings the edges of which are denoted at 22 and 23, respectively, in FIG. 2. The sealing members 26* and 21 are carried by bellows 24, FIG. 1, to which air under pressure is supplied so that the sealing members are forced against the flat end walls 9' and It The thrust can be chosen such as to relieve the ball bearings 6 from axial forces.

Mounted in recesses in the sealing members 21 are support rollers 25 which initially may be located entirely inside the surface of the sealing element but upon a certain wear of the sealing element come into contact with flat end walls 9 and lit. The support rollers take the main thrust such that the sealing surfaces only just come into contact with each other. Consequently, the sealing surfaces will be subject to moderate wear. The air supplied to the bellows 24 leaks past the rollers and cools the rollers as well as the sealing surfaces.

The sealing members and bellows are secured to plates 26 which are bolted to the housing 1 and the cover 1a, respectively. The regenerator material 14 consists advantageously of a corrugated foil-shaped material of the ceramic type. These foils are arranged in the chamber 13 such that parallel narrow ducts formed by the corrugations extend through the heat exchange member, as will be seen from FIG. 1. The ceramic material is light and has a very large surface with resulting high capacity in spite of the fact that the thermal conductivity of the material is low. 'The last-named property is advantageous from the point of view of minimizing the transport of heat from the hot end to the cold end of the material. It is true that this material is very brittle, but since it is divided in a plurality of small sections provided in individual chambers, the material will not be subjected to considerable mechanical stresses. In case of damage individual sections can be exchanged. It may happen that a heat exchanger takes fire. In the heat exchanger described the fire is not likely to spread over the entire heat exchange member, and since the ceramic material is highly heat-resistant, it is not likely to be damaged.

Although not shown in the drawing, the converging lateral surfaces of the chamber 13 are corrugated to increase the stiffness thereof. The corrugations are displaced relative each other such that the corrugations of one element project into the corrugations of an adjacent element in the assembly.

Said corrugations of the walls of the chamber do not extend throughout the entire height of the walls. At the ends of the walls there are provided fiat wall portions. Between these flat portions and the heat absorbing material there are inserted sealing rings in conformity with the wedge-shape of the chamber, said sealing rings preventing the fiuids from passing between the walls of the chamber and the heat absorbing filling material. The

. resilient engagement with the sealing material; 1:

g, seating rings may be V-shaped in cross section so as to be resilient, one limb of the V bearing upon the inside of thewall of the chamber and the other one bearingupon; the filling material. The two contacting edgesmay be. provided with outwardlybent flaps which are received in the filling material and inthe recesses in the .Wall of the chamber, respectively, such as to localize thefilling. material in its position-in the chamber." These sealing rings which may be replaced by separatelstrips serve three purposes. They act as sealing members, they retain the filling material elastically to prevent damage by' a thermal expansion of the chamber, and they lock the filling material'axially of the chamber.

' partition 4 in the cover In is locatedsuch that chain! Inaccordance withthe invention, the.annular zone 'of i the part of the heat exchange. member; confronting .the

apertures 11 and 12 extends radially over 50 to 90% of the radial extent ofthe chambers 13. As" a resultthereof,

the fluids are able to distribute themselves over. the enwill be uniformly utilized even in case of a relatively small distance between the end surface of the filling material. In addition, the axial.

and the plane of the apertures. extension of the case 7 may be small, resulting ina'low Weight of the heat exchanger. axial extent of the heat exchange member, special measures a may be taken'to ,spreadthe fluids. For example,;a'conical perforated screen, such as a conicalnetting', maybe.

provided immediately inside the apertures 11' and 12 such as to guide part of thefiuid outwardstowardthe walls" of the container 13.. iAsimila'r effect can be obtained. if

the end surface of the filling material which confrontsthe: apertures Hand 12 is provided .with'an'additional lining.

' tire end surface of the filling material which consequently.

In order to minimize the V of steel wool,' mineral wool or thealike which -is;retained in place by a suitable netting. .Asia result of this measure; 1

the resistance to flow will be increased just at these parts of the filling material which are indicated at Main FIG. 1.

1, theresult'being a balancedfluid flow. It should be noted that these additional linings also take part in the exchange of heat. Instead of the provision of "special linings the filling material itself may be profiled in a cor-;

responding manner.

While two circular apertures of ditterent sizes are shown: in thedrawing, the invention is not limited to this shape and number of apertures. For example, the two aper:

tures may be replaced by'a single aperture conforming to'the shape of the chamber.. In thiscase, packings, 0-1

rings or similar members have to be provided for efie'cta.

5 ing a seal between the apertures of the chambers and theend walls 9"and1t) of the case -7, and theehambers have.

to 'be provided with bellowsalike ;:COl.lars garou'nd'the apertures'suchthat the edges of the apertures are kept in In the embodiment exemplified the heatexchange mer'n V 7 her is driven by a hydraulic motor 27."

7 As will be seen from FIG.2,.the' opening 22 in the sealing member 20 for the gas section extends through'a considerably greater angle than the openings 23 inthe sealing member 21 for the air section( However, the

bers 2 and 3 extend substantially; throughanganglepf; 180. Insertedin the cover, are guide vanes28 which dei flect the air from-'the'inlet duct5 also toctheends of the chamber 2 so as to contributeto'a uniforminflow through the openings 23 and. to cool a comparativelyflarge"por-2 7 tionof theoutside of the cover- 1. Y 1 a The invention is not 'limited'to the:illustratedand de scribed embodiment and. .can be modified asto 'the de tails thereof,.within the scope .ofjthe annexed claims.

For example, theouter wall "7 andthe inner, wall *8 "of q the case ofthel=heatexchange -membermay berecessed, such as inthe form oflattices, in "order, to reduce their weight. Ifdesired; the; sealing members 2tla'nd Zljmay be replaced .by a single'lonei Even other: me. are cenceivable and need not be' describedj What is. claimedhisiv difications V 1. A. rotary regenerative heat; exchanger of the axial E flowtype, particularly for. gas turbine power plants,- comprising a stationary housinggan annular" heat; exchange"; I member mounted for rotationinsaidhousing and hayingfi radial end walls,driving meansltor said heatlexchange lmemberysaid housing being providedxwith an. inlet and n ofrotationof the heat exchange member,"sealing means between said radial end walls, and, said housing, and an inlet duct for. said fluid; to befheated' 'extending axially; through the. center of said annular heat [exchange imemberi to said distributing chamber; said duct. supporting 'bear.-=

ings for. said rotatable." heatfexchange member. 1 x 2.. A regenerative heat exchanger as claimed in claim 1-, and which further includes guide vanes; in'said distributing {chamber for, deflecting fluid from said" inlet 5 duct evenly to the receptacles of said heat exchange member.

3. A-regenerative heat exchangeras claimed inaclann;

'1 and which further includes bellow membersfilled with a fluid under p'ressure and forcing saidYsealingjmeans; into contact with said radial end walls o f said annular'; j heatexchange member.f 7 7 References 5 Cited-by the Examintr v I I UNITEDQSTATESPATENTS 1,746,598"

um. printedapplication .1510. toslazsafa/ ss.

- cHARLassUKALojrim-ary Examiner, 1 

1. A ROTARY REGENERATIVE HEAT EXCHANGER OF THE AXIAL FLOW TYPE, PARTICULARLY FOR GAS TURBINE POWER PLANTS, COMPRISING A STATIONARY HOUSING, AN ANNULAR HEAT EXCHANGE MEMBER MOUNTED FOR ROTATION IN SAID HOUSING AND HAVING RADIAL END WALLS, DRIVING MEANS FOR SAID HEAT EXCHANGE MEMBER, SAID HOUSING BEING PROVIDED WITH AN INLET AND AN OUTLET FOR A HEAT EMITTING ELASTIC FLUID AND AN INLET AND AN OUTLET FOR AND ELASTIC FLUID TO BE HEATED AND A COVER COMPRISING A DISTRIBUTING CHAMBER AND A COLLECTING CHAMBER FOR THE FLUID TO BE HEATED AND THE HEAT EMITTING FLUID, RESPECTIVELY, A PLURALITY OF RECEPTACLES IN SAID HEAT EXCHANGE MEMBER, SAID RECEPTACLES BEING FILLED WITH A HEAT EXCHANGE MATERIAL AND ARRANGED CIRCULARLY AROUND THE AXIS OF ROTATION OF THE HEAT EXCHANGE MEMBER, SEALING MEANS BETWEEN SAID RADIAL END WALLS AND SAID HOUSING, AND AN INLET DUCT FOR SAID FLUID TO BE HEATED EXTENDING AXIALLY THROUGH THE CENTER OF SAID ANNULAR HEAT EXCHANGER MEMBER TO SAID DISTRIBUTING CHAMBER, SAID DUCT SUPPORTING BEARINGS FOR SAID ROTATABLE HEAT EXCHANGE MEMBER. 